POSSIBLE SOLUTION TO THE COSMOLOGICAL-CONSTANT PROBLEM

Classically, the unimodular theory of gravity with a constrained determinant g is equivalent to general relativity augmented by an arbitrary cosmological constant, which arises as an integration constant. At the quantum level we argue that an integration over should be included in the Euclidean path integral for the vacuum functional. The fully renormalized Î=0 overwhelmingly dominates all other contributions yielding a zero observed cosmological constant. While the technical part of our argument is similar to that of the εwormholeε argument, the two approaches are logically different. © 1990 The American Physical Society.